The first monsoon depression of season 2021 is likely to form over the Bay of Bengal shortly, accentuating the monsoon current and rainfall over the country. The weather system will precipitate over the Myanmar region and later enter the Bay of Bengal, as it usually happens on quite a few occasions during the southwest monsoon season. The formation of a monsoon system early in the season indicates a good beginning and vindicates the timely progress of the monsoon stream over the northeast and east India.
A cyclonic circulation is likely to form over Myanmar on 07th June and enter the Gulf of Siam the next day on 08th June. On 09th June, the weather system is expected to move over the Northeast Bay of Bengal. Within the next 24 hours, it is likely to shift closer and also move along the Bangladesh coast to park itself over the Head Bay of Bengal. Over this area, monsoon systems have very little space to maneuver and invariably enter the land with Odisha and West Bengal as their favorite destinations. These timelines as of now may not be strictly followed and may vary by 12-24 hours.
During the southwest monsoon season, the frequency of depression or low-pressure area is rather high over the Bay of Bengal than the Arabian Sea. Their incubation period over the ocean generally lasts for 2-4 days. Once the systems move inland and track across the Indo Gangetic plains, they become instrumental in establishing the monsoon trough, the chief driver of monsoon rainfall. The monsoon trough, also named as Inter Tropical Convergence Zone (ITCZ) along with these monsoon depressions are considered lifelines for sustaining and controlling the rainfall distribution through the season.
The maiden system of the monsoon season always has the vigor to give the maximum push to the monsoon and take the stream to the hinterland. Consequentially, it draws the monsoon line, popularly called 'northern limit of monsoon' and the next system then does the honor to take the baton further.
